Fire officials confirmed Wednesday that someone in the home was trying to extract THC from marijuana when an ignition source came in contact with vapors, causing the explosion.

"The buildup of butane vapors within the apartment came in contact with an ignition source and an explosion ensued," Tewksbury Fire Chief Michael Hazel said. "The process was being performed on and around an electric stove within the apartment. A number of full and empty and butane cylinders were found at the scene. This was a very dangerous situation for the residents and the firefighters."